Exercise reduces preexisting atherosclerotic lesions in LDL receptor knock out mice

Exercise is recommended both as a prophylactic and also as a therapeutic approach for patients with established coronary artery disease. In this study, we investigated the effect of a normal chow diet, with or without exercise in LDL r ^-/- mice with preexisting atherosclerotic lesions. A total of 28 LDL r ^-/- mice (LDL receptor knock out mice, 4-6 weeks old) were fed a high fat, high cholesterol diet (inductive phase). At the end of the 3 months, eight mice were sacrificed, and plasma autoantibodies to oxidatively modified proteins, cholesterol levels, and surface area of the lesions in the aorta were determined. The remaining mice were divided into two groups, and placed on a normal chow diet alone, or normal chow and exercise for three more months (regressive phase). Plasma autoantibodies to oxidatively modified proteins and cholesterol were measured along with the lesion size. Compared to the group of animals at the end of the inductive phase, both the groups of animals in the regressive phase had very low levels of plasma cholesterol and autoantibodies, and almost a 50% reduction in the aortic lesion area. The group that was exercised had the lowest levels of autoantibodies and aortic lesions as compared to the group without the exercise. However, the plasma cholesterol levels were comparable in both groups. This study demonstrates that reduction of preexisting atherosclerotic lesions is accelerated dramatically by exercise in LDL r ^-/- mice.